BMW 116i E87

Both the N45 and N43 engines use a timing chain with plastic guides that degrade over time. On the N45, the chain is relatively thin and stretches gradually, typically requiring replacement around 100,000 km. A rattling noise at 2,000-2,700 rpm or on cold start indicates wear. On the N43, the problem is more severe: the plastic guides can fracture completely, with fragments falling into the oil pan and blocking the oil pump strainer. This causes oil starvation and can lead to catastrophic engine seizure. BMW ran a testing campaign for N43 timing chains but did not replace them preventively. Independent specialists charge approximately €800-1,200 for chain, guides, and tensioner replacement. If engine damage has occurred from oil starvation, a replacement engine costs €2,500-3,500 installed.

The N43 engine uses high-pressure piezo direct injectors that are expensive and failure-prone. When an injector fails, it causes misfires that foul the spark plugs, which then overload and damage the ignition coils. This creates a cascade of failures that makes diagnosis confusing. Simply replacing coils and plugs without addressing the root cause (faulty injectors) leads to repeated failures. New OEM injectors cost approximately €200-300 each, plus coding to the ECU. Replacing all four injectors with new plugs and coils at an independent specialist runs €800-1,500. Used injectors are available for €50-100 each but carry risk. This issue typically appears between 80,000-150,000 km. The N45 engine (2004-2007) uses conventional port injection and is not affected by this problem.

The N43 engine has a NOx sensor for its lean-burn direct injection system. This sensor is prone to failure, causing unstable engine speed, increased fuel consumption, and persistent fault codes. Symptoms include hesitation on acceleration, rough idle, and occasional misfire-like behaviour. The sensor is manufactured by Continental and OEM replacement is recommended, as aftermarket sensors often do not work properly. The sensor costs approximately €300-400, with about 1 hour labor for installation. Some owners use a NOx emulator (€100-150) as a workaround, but this disables the lean-burn function and may not pass emissions testing. Average sensor lifespan is approximately 150,000 km. This issue does not affect the N45 engine (2004-2007).

Both the N45 and N43 engines use VANOS (variable valve timing) solenoids that can clog with oil sludge or develop external leaks through degraded O-ring seals. Symptoms include rough idle, poor acceleration, increased fuel consumption, and VANOS-related fault codes. The O-ring seals harden over time and are a common source of minor oil leaks around the solenoid housings. Cleaning the solenoids and replacing O-rings is a straightforward job at €50-100. If the solenoids themselves have failed internally, replacement costs €150-300 for parts plus about 1 hour labor. In some N45 cases, the VANOS sprockets themselves can develop play and rattle, requiring more expensive sprocket replacement at €300-500.

The valve cover gasket on both N45 and N43 engines hardens and shrinks over time, allowing oil to seep out. Oil can drip onto the exhaust manifold, creating a burning smell and smoke, or pool around the spark plug wells, contaminating the ignition coils and accelerating their failure. The gasket itself costs €30-60, but the job requires 2-3 hours of labor due to the need to remove intake components. Total cost at an independent shop is €200-400, while BMW dealers charge €400-600. On the N43, the valve cover also houses the PCV (crankcase ventilation) system, and if the PCV diaphragm fails, the entire valve cover may need replacing at €300-500 for the part alone. This is a near-certainty on cars over 10 years old.

The E87 rear subframe is susceptible to corrosion on its lower edges where it is exposed to road spray, stone chips, and salt. This is well documented across the E87 community, with some owners reporting subframes corroded so severely they cracked, potentially damaging brake lines. Finding a rust-free replacement is difficult as most used subframes are also corroded. Treatment involves wire-brushing surface rust and applying rust-inhibiting coatings like POR-15 (€300-500 professionally). If the subframe needs replacement, a used unit plus fitting costs €800-1,200. Cars from coastal areas or regions with heavy road salt use are most affected. Preventive underbody wax treatment every two years significantly slows progression.

The E87 boot area is prone to water ingress through the rectangular vent panels behind the trim and through poorly sealed rear light housings. Water accumulates and soaks the PDC (parking distance control) module housed in the right side of the boot. A waterlogged PDC module sends corrupted signals on the CAN bus network, causing cascading electrical faults including complete instrument cluster failure (speedo, rev counter, temperature gauge all go dead), random warning lights, and central locking issues. DIY resealing of vents and light housings costs €10-20. If the PDC module is damaged by corrosion, replacement costs €150-300. If other modules on the CAN bus are affected, diagnosis and repair can reach €500.

Manual-equipped 116i models develop clutch judder when moving off, especially from cold and on inclines. The dual mass flywheel develops excessive play, producing vibration felt through the pedal and entire drivetrain. Combined clutch and DMF replacement costs €700-1,200 at an independent specialist, with parts (flywheel approximately €250, clutch kit approximately €150) plus 4-5 hours labor. This is a standard wear item that typically needs attention between 100,000-150,000 km depending on driving style. Urban stop-start driving accelerates wear significantly.